Yolanda: The particles are close to each other, slide around each other

2. Only solid’s particles don’t move. True or False. Why?

because the density of metal is greater than that of water.（vickie）

Question 2: why light travel through air to water will produce refraction?

because light is refracted when it spreads through air into water, because light is in a uniform medium when it propagates in the air, and when it enters the water, the density of the medium changes from lower density air to higher density water.（vickie）

Danielwu：The faster the speed, the greater the resistance

increase.Oscar

2.why an object floats

Because of its low density.Oscar

36.66666666666667J -- Yade

conduction

2)The air resistance of a car can be reduced by what

let the streamline shape

kevin

Science relationship

Angelia

Light refraction

Why the iceberg can floats on the water？

Angelia

Because the density of ice is relatively small and the density of water is relatively high, the ice will float on the water.

1️⃣ Explain why an object float

Danielwu：Because it's less dense

2️⃣Explain how density affects the way an object floats

Danielwu：Low density will float, high density will sink

Because the density of foam is smaller than that of water

2.What is the density of water?

水的密度是1g/cm³,10³kg/m³（t=4℃）。

Susan

Light is Absorption or reflection by opaque objects

--Yade

Because Light is Absorption or reflection by opaque objects

—Raymond

2.two sources of light

lamp,sun

Oscar

金属的密度大于水的密度。

光是直线传播的吗？。

Yes,light transfer in straight line (vickie)

2.Identify upthrust as a force

Light are faster then______

joe

1，moov，straight

2，sound

kevin

A.a translucent material transmits light

B.a translucent material absorbs all light

C.a translucent material absorbs some light and the rest is reflected

D.a translucent material scatters light as it passes through

What’s the properties of solids liquids and gases ?

Danielwu：thermometer

2.What is the three states of matter?

A length

B degrees

C heat

D temperatu

D- Jason

2.The phenomenon and properties of light?

1:mass volume

2:The speed is faster than the sound

Amy

2.what are the different states of substances?