real science for today's homeschooler

Measuring Volume

Measuring Volume

Many science activities rely on taking an accurate measurement of the volume of liquids and solids. Below you’ll find a reference for how to measure the volume of different types of matter. Activities in this blog that require students to measure volume will include a link back to this page for reference.

VOLUME OF A LIQUID

This one is easy . . . add the liquid to a container that measures volume! 🙂 One suggestion would be to find measuring containers that measure in milliliters (mL)and (L) so that children become familiar with metric measurements.

VOLUME OF A REGULAR SOLID

A “regular” solid means one that has a specific geometric shape whose dimensions can be measured accurately with a ruler. Here are some of the basic formulas used to measure the volume of geometric shapes:

formulasBe sure to measure lengths in metric units such as centimeters (cm) or millimeters (mm). All volume measurements will then be in cubic centimeters  or cubic millimeters.

VOLUME OF AN IRREGULAR SOLID

The water displacement method is typically used to measure the volume of an “irregular solid,” a solid that lacks a regular geometric shape whose dimensions can be measured with a ruler. To use the water displacement method you will need a container that will hold the object to be measured, and that is marked in metric units, preferably milliliters.

1. Fill the container with enough water to cover the object.

2. Record the amount of water in the container, preferably in milliliters.

3. Insert the object to be measured, being careful not to let it “plop” in and splash water out!

4. Record the new water level in the container.

5. Subtract the two water levels to determine the amount of water that was “displaced” (moved out of the way) when the solid object was inserted.

6. Because 1 milliliter of water = 1 cubic centimeter of water, you can assume that the volume of water displaced in milliliters is the same as the volume of the solid object in cubic centimeters.

Many of the activities in this blog will require that students find the volume of different substances. This page will be linked so you can easily return for a refresher on measuring volume! 🙂

 

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Rotational Motion with a Pinwheel

Rotational Motion with a Pinwheel

Kids love to play with pinwheels. Whether you buy one at the store or make your own (pinwheel making tutorial), add a little Physics to the fun!

1. Use a string and ruler to measure the outside distance around the outside of the pinwheel.

2. Mark one spot on the pinwheel in some way. Use color, a piece of tape, etc. Just make sure the mark is very visible, even when the pinwheel is spinning.

3. Have your child practice watching the pinwheel in motion and counting each time the pinwheel makes a complete revolution. (When the mark on the pinwheel goes all the way around and returns to the same spot.) Move on to practicing counting exactly 10 revolutions. When your child has this down, move on to step 4.

4. Use a stop watch to measure the time it takes for the pinwheel to make 10 revolutions. Repeat 5 times, then average the 5 trials to get the “average time” for 10 revolutions.

5. Divide the average time by 10 to get the time for 1 revolution.

6. Calculate the speed at which the outside of the pinwheel was spinning by dividing the distance around the outside of the pinwheel (step 1) by the average time for 1 revolution (step 5). Your child has just calculated the rotational speed of the pinwheel!

To extend, repeat using different sources of “wind” to move the pinwheel at different speeds. Add a weather component by repeating on consecutive days to compare the wind strength. Older children may find it interesting to compare the actual wind speed (use a local weather app) to the speed of the pinwheel rotation. Look for patterns and mathematical relationships between the two.

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Water Conservation

Water Conservation

How many times do you have to remind your kids . . . “Turn off the water!” . . . or, “Turn off the light when you leave the room!” Kids are forgetful and they sometimes need help developing good conservation habits. Here’s a simple activity that will make your kids aware of how much water they can waste simply by brushing their teeth!

1. Find a large bowl that will just fit into the sink to collect water running from the faucet.

2. Have your child brush their teeth as they typically do, leaving the water running the entire time.

3. When they finish brushing and rinsing, measure the volume of the water collected in the bowl. You can use any measurement that works for the tools you have on hand. Cups might be the best, as you can convert your final measurements into gallons. Students have a good concept of how much a gallon is when they think about a gallon of milk.

4. Repeat the process, but this time, have your child turn off the water when they are not using it to wet the toothbrush, rinse, etc. When finished, measure the amount of water used.

5. Have your child subtract the difference between the amount of water used when running the faucet the entire time and when only turning it on when necessary. Convert to gallons: 1 gallon = 16 cups.

6. Finally, have your child calculate the number of times they brush their teeth in one year. Multiply by the amount of water that can be saved at each brushing. The amount of water wasted each year by letting the faucet run is surprising!

7. To extend for older children . . . multiply that amount of water by the number of people in your household to see how much water the family could save in one year. Then, help your child read a recent water bill to determine how much your utility company charges per gallon of water. Use that figure to calculate the amount of money your family could save by turning off the faucet while brushing your teeth!

Disclaimer: If you follow this project through to the very end, be ready for your child to transform into the “faucet police”! 🙂 Once children “see” the results of conservation techniques they do tend to become aware of what everyone around them is doing!

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Calculate Speed While Encouraging Exercise

Calculate Speed While Encouraging Exercise

We all know that kids have a lot of energy. Put that energy to good use by combining a physics lesson, a math lesson, and some good exercise! All you’ll need is an energetic kid, a tape measure, a stopwatch, and a safe place for your child to run.

Calculating Speed

1. Pick out a “track” that your child can run safely. Select a distance appropriate for your child to run several times.

2. Help your child measure the distance of the selected track with the tape measure. You can measure with any units: yards, feet, meters, etc. Have your child record the track distance.

3. Measure the time it takes for your child to run the selected track. If possible, measure the time in seconds. Record.

4. Introduce the formula used to calculate speed:  speed = distance / time

Depending on the math level of your child, help them calculate their speed by dividing the distance of the track by the time it took to run it. Older children can calculate speed using long division. For younger children you may want to introduce the usefulness of technology by showing them how to get their answer with a calculator.

5. Repeat the run with the same track, or a different one as long as your child is interested and energetic. Challenge them to improve their speed with each run.

As an extension of the lab, students can compare their speeds when a) wearing different types of shoes, b) running on different surfaces, or c) running courses of different lengths. Any of these options will increase your child’s interest in the lab, as well as give them extra practice with division . . . and a little more exercise!

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How much would you weigh on different planets?

How much would you weigh on different planets?

What is weight?

Your weight would be very different if you lived on another planet. Assuming your size didn’t change, why would your weight change? To understand this, you have to know what the term “weight” really means.

A term that’s often confused with weight is “mass.” Mass is the amount of matter (stuff) that something is made of. Your mass wouldn’t change no matter what planet you happened to be standing on. But “weight” is not the same as mass.

Weight is a measure of the force with which gravity pulls down on your mass. So, if gravity changes, so does your weight! The gravity of a planet is determined by the size (mass) of the planet. Heavier planets exert more gravitational force than lighter planets.

 What would you weigh if you visited a different planet?

To calculate your weight on different planets, multiply your weight on Earth in pounds by the “gravitation factor” in the chart below. The Moon is also included.

Celestial

Body

Gravitation

Factor

Your

Weight

Mercury

0.38

Venus

0.91

Moon

0.17

Mars

0.38

Jupiter

2.54

Saturn

1.08

Uranus

0.91

Neptune

1.19

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How old are you on a different planet?

How old are you on a different planet?

What is a year?

We measure age in years. A year is a unit of time equal to the number of days it takes the planet to travel all the way around the Sun and return to its same location along its orbit.

Earth takes 365.25 days to make a trip around the sun, so our calendar year is usually 365 days. Once every four years, one day is added to the calendar at the end of February to account for the 0.25 day each year. That’s why we have a “leap year” every four years.

If you lived on another planet, a year would not be 365 days because each planet takes a different amount of time to make a trip around the Sun, based mainly on its distance from the Sun. (The farther away from the Sun, the larger the orbit and the longer it takes to go around the Sun.) Assuming you still referred to a “year” as one trip around the Sun, your age in years would be very different from what it is on Earth.

 How many years old would you be on different planets?

To calculate your age on different planets, first, divide your age by 365.25. Then multiply that answer by the number of days in the “year” of each planet. You can find that information in the table below:

Planet

Days in Year

Your Age

Mercury

87.97

Venus

224.70

Mars

686.67

Jupiter

4331.87

Saturn

10760.27

Uranus

30604.65

Neptune

60189.48

 

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