Melting, Freezing and Boiling Points of Liquids
Grade Level: 8th; Type: Physical Science
This project compares different liquids and determines differences in freezing, melting and boiling points.
- Which liquids freeze at the highest and lowest temperatures?
- Which liquids don’t freeze in a conventional household freezer?
- Which liquids melt at the lowest and highest temperatures?
- Which liquids boil at the lowest and highest temperatures?
- Are the liquids that freeze, melt and boil at the lowest and highest temperatures the same?
- What properties affect these differing temperatures?
We are surrounded by all types of liquids: water, oils, vinegar, soda, juice. All of these liquids look, smell and feel different. How do these liquids differ in terms of boiling, freezing and melting points? What is it about them that does this?
- As many different liquids as you can find. Suggestions: water, juice, soda, different types of oil (canola, corn, coconut, olive), wax, vinegar, chocolate, etc.
- A cooking or candy thermometer
- A small pot to use on the stove
- A freezer
- An adult to supervise
- Notebook and pencil to record observations
- Note observations of each item at room temperature. Is it liquid or solid?
- Determine the freezing point if it is a liquid by placing it in the freezer with a thermometer inside. Check it every 10 minutes to see if it has solidified, and note the temperature when it has.
- Measure the melting temperature for each of the frozen items. For those that are solid at room temperature, slowly heat in a double-boiler (a bowl inside of a pot with water at the bottom will work: be sure to have the thermometer ready to measure the temperature when it becomes a liquid). Determine the melting point of each item.
- Heat each liquid in the pot until it just starts boiling. Measure the temperature with the thermometer.
- Record all results and make a chart comparing each liquid. Note which liquids have the highest and lowest points overall for freezing, melting and boiling.
- Note whether the lowest and highest points are the same items for freezing, melting and boiling.
Terms/Concepts: physical state, room temperature, melting point, boiling point, freezing point, liquid, solid
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